1. Field
Apparatuses consistent with exemplary embodiments relate to a complex spatial light modulator for modulating both phase and amplitude of light and a three-dimensional (3D) image display device including the same.
2. Description of the Related Art
As three-dimensional (3D) movies have recently been gaining more popularity, research is being actively conducted on techniques related to 3D image displays. 3D image display devices display 3D images based on binocular parallax. Currently commercially available 3D image displays use the binocular parallax between a viewer's eyes to provide a left-eye image and a right-eye image having different viewpoints to the left and right eyes of the viewer, respectively, thereby allowing the viewer to perceive a stereoscopic effect. 3D image display devices are classified into glasses type 3D image display devices requiring use of special glasses and non-glasses type 3D image display devices not requiring assistance of special glasses.
However, when a viewer views 3D stereoscopic images displayed by a 3D image display device using binocular parallax, the viewer's eyes will often tire. Furthermore, 3D image display devices only providing two viewpoints, i.e., the left eye's viewpoint and the right eye's viewpoint, have a limitation in providing a natural stereoscopic effect because they cannot reflect a change in viewpoints as a viewer moves.
Holographic 3D image displays have been proposed to provide more natural stereoscopic images. However, in order to realize a holographic 3D image display, there is a need for a device for controlling both amplitude and phase of light. When images are displayed using a device for controlling either the brightness (amplitude) or phase of light, twin images with zero-order diffraction beams, and speckle noise may be present in the images, thereby causing degradation of image quality.
A holographic 3D image display may include a holographic optical element in order to control an amplitude of the light. However, such a device, for example, a Bragg grating, is composed of birefringent materials, and is therefore polarization-dependent. Thus, the use of such a holographic optical element also requires the use of a polarizer and a half-wave plate, or other polarizing optical elements in order for the amplitude of the light incident on the holographic optical element to be controlled. Such additional elements add to the complexity and cost of the device. Furthermore, the “radiation effect” problem of current holographic optical elements is known. The photopolymer function of current holographic optical elements degrade over time, causing the optical performance of the image display apparatus to decay over time. Such polarization-dependent optical elements are also expensive and difficult to manufacture and are limited in size.